Carburettor Settings - Husqvarna 545RX Workshop Manual

H L
T
Fuel system
Fit the carburettor cover to the carburettor.
Check that the choke and the throttle
valves are working.
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Put the air hoses (C and D) in place and
screw the cover (B) tight.
Put the air fi lter in place and snap on the
air fi lter cover.

Carburettor settings

!
WARNING!
When testing the engine in connection with carburettor adjustment,
the clutch and clutch cover must be mounted together with the shaft
and angle gear under all circumstances
Otherwise there is a risk of the clutch becoming loose resulting in
serious personal injury.
Function
The carburettor has the task of supplying a combustible fuel/air mixture to the cylinder.
The amount of this mixture is controlled by the throttle.
The mixture's composition of fuel and air is controlled by means of the adjustable "H"
and "L" needles.
The needles must be correctly adjusted in order for the engine to give maximum power
at different speeds, run steadily while idling and to react quickly when accelerating.
The setting of the carburettor can vary a little depending on the humidity, temperature
and air pressure.
L = Low speed needle
H = High speed needle
T = Idle adjustment screw
• The fuel quantity in relation to the air fl ow permitted by the throttle opening is adjust-
ed by the L and H jets. Turning the needles clockwise gives a leaner fuel mixture (less
fuel) and turning them anticlockwise gives a richer fuel mixture (more fuel). A leaner
mixture gives higher revs while a richer mixture gives less revs.
• The T-screw regulates the position of the throttle while the engine is idling. Turning
the screw clockwise gives a higher idling speed while turning it anticlockwise gives a
lower idling speed.
4. Insert the 4 screws (A) in the carburet-
tor cover.
5. Check that the choke valve in the car-
burettor and the choke control in the
cover are both open.
6. Slide the cover in place on the carbu-
rettor and tighten screws (A and B).
7. Check that the choke and throttle
valves open and close as intended.
8. Place the hoses (C and D) on the
carburettor and the air supply valve.
9. Screw the cover (B) tight.
10. Put the air fi lter in place and snap on
the air fi lter cover.
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